The present invention relates to a method and system for securing a substrate such as paper and the like against counterfeiting, photocopying, and facsimile transmission and an applicator and paper for use in the method and system and with the applicator, that is to say paper which when carrying information in a conventional black or similar dark color cannot be readily photocopied or transmitted by telefacsimile in a visually readable manner and is resistant to counterfeiting.
The present day availability of improved photocopiers has increased the problem of rendering documents or portions thereof resistant to photocopying in a readable manner. Moreover, the latest generation of color photocopiers has made it easier to counterfeit valuable documents. Antiphotocopying paper which is successful in preventing visually readable photocopying by most present day photocopiers is described in U.S. Pat No. 4,522,429 (Gardner et al) issued Jun. 11, 1985, U.S. Pat. No. 4,632,429 (Gardner et al) and U.S. Pat. No. 4,867,481 (Gundjian).
U.S. Pat. No. 4,522,429 teaches the use of antiphotocopying paper having a color with a reflection spectral response of less than about 10% for light with a wavelength below about 600 milimicrons and yet which is sufficiently visually contrasting with information, when such information is typed thereon or otherwise applied thereto, to enable such information to be read by the human eye when the paper is viewed under which light.
U.S. Pat. No. 4,632,429 teaches the use of antiphotocopying paper with a front face having a color with a reflection spectral response which is effectively zero for light with a wavelength below about 625 millimicrons and less than about 1% up to about 1,000 millimicrons so as to render the paper substantially incapable of being photocopied in an information readable manner, after substantially non-translucent information has been typed or otherwise applied to the front face, the paper being capable of transmitting visible light from a rear face to the front face to cause sufficient contrast between the substantially non-translucent information and the transmitted light to enable the information to be read by a human eye viewing the front face of the paper when visible light is transmitted through the paper from the rear face to the front face thereof.
Anti-photocopying paper of the type described in the abovementioned patents satisfactorily fulfills most present day needs, and represents a very significant improvement over prior proposals which were not successful in practice. Such paper is also resistant to transmission by telefacsimile.
The increasing photocopying ability of new generation photocopiers presented a need for still further improved anti-photocopying paper.
A further improved anti-photocopying and anti-telefacsimile effect has been achieved by the spatial, spectral modulation of the paper reflectance at a specific single or preferably, multiple spatial frequencies as disclosed in U.S. Pat. No. 4,867,481 (Gundjian).
Given all the above, it has, however, been recognized that the requirement for the feature of uncopiability on a document is often limited to a selected and limited portion of the said document. Furthermore, having also recognized that generally, it is only after the printing, typing or otherwise transfer of the information to a paper, that the portions of the latter that are required to be secured and hence to exhibit qualities of uncopiability are identified, the present invention has been worked out.